Unnecessary morbidity and mortality is an important problem which leads to increased health-care costs and can ultimately result in premature death. It has been estimated that approximately two thirds of mortality is due to potentially preventable causes - 1.2 million deaths (65%) and 8.4 million years of life lost before age 65 (63%). Principal factors associated with unnecessary morbidity and mortality include tobacco use, high blood pressure, improper nutrition, lack of screening and prevention services, alcohol abuse, and injury. This project uses longitudinal data from the Baltimore Longitudinal Study of Aging (BLSA) and other studies to examine the influence of modifiable risk factors on the occurrence of premature deaths and unnecessary morbidity and disability. Identification of risk factors can lead to primary prevention efforts. Examples of BLSA research on the identification of modifiable risk factors include: studies of the relationship between total white blood cell count and coronary heart disease, noise exposure, blood pressure, and smoking in relation to hearing loss; pulmonary change as a risk factor for cardiac events (see Project Z01 AG 00634-05 LSB); and hormonal factors as a risk factor for prostate disease (see Project Z01 AG 00633-05 LSB). One example of BLSA research on secondary prevention practices is the ongoing research to improve the accuracy of the prostate specific antigen test to allow screening for early detection of prostate cancer (see also Project Z01 AG 00633-05 LSB). Information from these studies can have an impact on the development of primary and secondary prevention programs to improve longevity and quality of life for many Americans.